Structural steel joist



Aug. 24' 1926.

E. C. HALL STRUCTURAL STEEL JOIST Filed Sept. 5 1924 Patented Aug. 24, 1926.

PATENT OFFICE.

EDWIN 0. HALL, OF MILWAUKEE, WISCONSIN.

STRUCTURAL STEEL JOIST.

Application filed September 5, 1924. Serial No. 736,134.

The invention relates to structural steel joists suitable for the floor construction of uildings.

The object of the invention is to provide a steel joist of simplified construction and light weight, whereby economies in manufacture are effected without sacrificing the strength and rigidity necessary for supporting heavy floor loads.

The invention further consists in the several features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings, Fig. 1 is a side view of a joist embodying the invention as applied to the floor construction of a building;

Fig. 2 is a side view of the joist members before assembly;

Fig. 3 is a view similar to Fig. 2 showing a modified form of the invention;

Fig. {l is a transverse sectional view of the joist taken on the line 4-4 of Fig. 1;

Fig. 5 is a transverse sectional view of the joist showing a modified top chord member; and

Fig. 6 is a transverse sectional view of the joist showing another modified construction.

In the drawings 10 designates the joist of Fig. 1 in which 11 is the top chord memberand 12 the bottom chord member.

The top chord member is a flanged structural shape, preferably an I-beam, although other shapes may be used, such as the angle 11 of Fig. 5, or the T 11" of Fig. 6. The bottom chord member 12 is preferably a light channel shape, but may be a flat bar, and has its end portions 15 inclined upwardly into welded abutment with the top chord member near the ends of the latter. In the modified form shown in Fig. 6 the bottom chord member is preferably extended to the end of the top chord member at their welded abutment in order to afford a broad bearing surface for the joist.

The web member 13 has its central portion 16 welded in parallel relation to the horizontal portion of the bottom chord member 12 and its upwardly inclined portions 17 extending into welded abutment with the top chord member 11. i The ends of the web member 13 extend downwardly from the last mentioned joints to form struts 18, preferably vertical, which have their lower ends welded into abutment with the bottom chord member at the junctions of its horizontal and inclined portions.

The central portion of the top chord member is supported by vertical struts 19, preferably of channel shape, welded thereto and having their lower ends welded into abutment with the web member 13 at the junctions of its horizontal and inclined portions.

For extremely long joists, it is desirable to add a second web member 14, as seen in Fig. 3, similar to the web member 13 of Figs 1 and 2. This modified construction is otherwise similar tothat of Figs. 1 and 2, the bottom chord member 12 and theweb members 13' and 14 being welded in parallel relation at their central portions, and having the inner struts 19 supporting the central portion of the chord member 11.

For the floor construction of buildings, the joists are supported by the ends of the top chord members on beams 20 or other leveled supports which may vary somewhat in span for a given length of joist, the bearing surfaces at the ends of the top chord members being of sufficient length to accommodate some variation in span, so that the joists may be manufactured in a few standard sizes. The joists are spaced at a suitable distance and retained in place on the beams by clips 21, the longitudinally adjacent 'oists having their ends resting on the beams in offset relation.

While various types of floors maybe laid on thejoists, a concrete floor of fireproof character is illustrated, wherein the concrete slab 22 is supported by a ribbed metal lath 23 attached to the top chord members.

For ceiling construction, expanded metal lath 24 is secured to the bottom chord members and to furring strips extending adjacent the beams 20 in order to obtain a flat plaster anchorage.

The employment of a flanged structural shape for the top chord member provides fiexural strength which permits the use of 1on panels, thereby reducing the number of fabricated joints to a minimum to lessen fabricating costs, and providing wide spaces for piping and wiring. Furthermore, the fiexural strength of the upper chord member is ample to resist end moments incident to the use of a fixed joist length on variable spans without the necessity for auxiliary reenforcement at the ends of the joist, and

the horizontal bottom flange of the top chord member presents a large bearing area at the supporting beams.

The single bottom chord member may be of light weight and need be only of suflicient strength for end panel requirements, since the web member is disposed to resist web stresses and additional bottom chord stresses in interior panel's.

The joist of the present invention provides an advantageous distribution of material to produce lightness without sacrificing strength and rigidity, and may be manufactured at low cost by reason of the small number of pieces and welded joints.

hat I claim as new and desire to secure by Letters Patent is:

1. In a metal joist, the combination of a flanged top chord member adapted to be supported at its ends over variable spans, a bottom chord member having its ends welded thereto and including an intermediate portion parallel to said top chord member, and a web disposed between said chord members in welded abutment therewith to form panels and including a member which integrally forms terminal loading struts and diagonals in tension meeting said bottom chord member at an intermediate portion.

chord for resisting additional bottom stresses in interior panels.

2. In a metal joist, the combination of a flanged top chord member adapted to be supported at its ends over variable spans, a bottom chord member having its ends welded thereto and including an intermediate portion parallel to said top chord member, and a web disposed between said chord members in welded abutment therewith to form panels and including a member which integrally forms terminal loading struts and diagonals in tension meeting said bottom chord member at an intermediate portion and said member forming between the lower ends of said diagonals a portion secured to said bottom chord member-for resisting additional bottom chord stresses in interior panels, and a pair of spaced loading struts disposed between the top chord member and the lower ends of said diagonals to form a central panel.

3. In a metal joist, the combination of an I-beam forming a top chord member adapted to be supported at its ends over variable spans, a bottom chord member having its ends welded to the lower flange of said I- beam in spaced relation to the ends of said I-beam, and a web disposed between said chord members in welded abutment therewith to form panels and including a member which integrally forms terminal loading struts and diagonals in tension meeting said bottom chord member at an intermediate portion for resisting bottom chord stresses in interior panels.

4. In a metal joist, the combination of a flanged top chord member of uniform section throughout its length and adapted to be supported at its ends over variable spans, a bottom chord member including an intermediate portion parallel to said top chord member and terminal portions forming diagonals welded at their upper ends adjacent the ends of said top chord member, and a web disposed between said chord members in welded abutment therewith to form panels and including a member which integrally forms terminal loading struts and diagonals in tension, said loading struts abutting at their lower ends against the lower ends of the diagonals of the bottom chord member and the diagonals of said web member extending from the upper ends of said struts and meeting said bottom chord member at an intermediate portion for resisting additional bottom chord stresses in interior panels.

In a metal joist, the combination of a flanged top chord member adapted'to be supported at its ends over variable spans, a bottom chord member having its ends welded thereto and including an intermediate portion substantially parallel to said top chord member, and a web disposed between said chord members in welded abutment therewith to form panels and including a terminal strut and diagonal in tension integrally formed, said web having a portion secured to said bottom chord member for resisting additional bottom chord stresses in interior panels.

In testimony whereof I atfix my signature.

EDWIN o. HALL. 

